Transfer mechanism having cam drive

ABSTRACT

A transfer mechanism having a substantially horizontal fixed support and a movable support adapted to raise vertically a workpiece resting on the horizontal fixed support, move the workpiece a predetermined distance substantially parallel with the horizontal fixed support and then lower the workpiece vertically onto the horizontal fixed support. The movable support is lowered vertically and travels horizontally in an opposite direction to return to its starting position. The motive force for the movable support comprises a cam means having a continuous single rotary input shaft and two alternately operative rotary output shafts. The cam means is so arranged that the input shaft alternately transmits rotary motion to one of the output shafts to produce 180* of rotary motion thereof, while the other of the output shafts is held stationary. The cam means then rotates the other output shaft for 180* of rotation while maintaining the first-mentioned output shaft stationary. One of the output shafts is operatively connected to the movable member in such a fashion as to cause vertical upward movement thereof during the first 180* of rotation of the same output shaft and downward vertical movement during the second 180* of rotation of the same output shaft, while the other output shaft is adapted to cause a horizontal back and forth movement of the movable support intermittent the up and down motion of the movable support respectively during the two alternating 180* rotary motion of the last-mentioned output shaft.

it States Patent Waara 5] kebo2%i972 [54] iRANSFER MECHANISM HAVING CAM DRIVE [72] Inventor: William A. Waara, Detroit, Mich.

[73] Assignee: Visi-Trol Engineering Company, Detroit,

Mich.

[22] Filed: June26,1970

[21] Appl.No.: 50,193

Primary Examiner-Edward A. Sroka Attomey-Hauke Gifford and Patalidis [5 7] ABSTRACT A transfer mechanism having a substantially horizontal fixed support and a movable support adapted to raise vertically a workpiece resting on the horizontal fixed support, move the workpiece a predetermined distance substantially parallel with the horizontal fixed support and then lower the workpiece vertically onto the horizontal fixed support. The movable support is lowered vertically and travels horizontally in an opposite direction to return to its starting position. The motive force for the movable support comprises a cam means having a continuous single rotary input shaft and two alternately operative rotary output shafts. The cam means is so arranged that the input shaft alternately transmits rotary motion to one of the output shafts to produce 180 of rotary motion thereof, while the other of the output shafts is held stationary. The cam means then rotates the other output shaft for 180 of rotation while maintaining the first-mentioned output shaft stationary. One of the output shafts is operatively connected to the movable member in such a fashion as to cause vertical upward movement thereof during the first 180 of rotation of the same output shaft and downward vertical movement during the second 180 of rotation of the same output shaft, while the other output shaft is adapted to cause a horizontal back and forth movement of the movable support intermittent the up and down motion of the movable support respectively during the two alternating 180 rotary motion of the last-mentioned output shaft.

1111 Claims, 4- Drawing Figures PAIENIEUFEH29 I972 3, 645,380

sum 1 OF 2 INVENTOR WILLIAM A. WAARA BY /M, 4; gram;

ATTORNEYS PAIENTEBmzs I972 SHEET 2 OF 2 R m M NA E o m l ATTORNEYS TRANSFER MECHANISM HAVING CAM DRIVE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to transfer mechanisms and to mechanisms adapted to transfer a plurality of articles from station to station in succession along a path, and, in particular, to a cam device adapted to alternately transfer a single rotating input to two rotating outputs in a selected alternating fashion for driving such transfer mechanisms.

2. Description of the Prior Art Heretofore, numerous driving mechanisms have been employed in all types of machinery, and in particular indexing cams have found extremely popular use in such driving mechanisms. They have many qualities which make them particularly desirable for use in various types of automatic apparatus. However, where a high degree of accuracy is required in the output shaft, existing types of structures require that they be manufactured to very exacting degrees of tolerance with the resultant effect that such structures are expensive to manufacture and, after a period of use, the wear encountered is very likely to cause such indexing cams to lose their accuracy.

The indexing cam structure in the patent to Lancaster et al. US. Pat. No. 2,986,949, provides an indexing cam which overcomes the problem of providing an acceptable degree of accuracy at the output shaft, yet is constructed in such a manner that it can be manufactured much more inexpensively than devices heretofore known. Such an indexing cam structure, although overcoming the disadvantages of prior indexing cam structures, is not particularly adapted for use in transfer mechanisms, and in particular is not adapted for use in transfer mechanisms of the walking beam type.

In order for such transferring devices of a walking beam type to be effective, they require the accuracy of the indexing cam structure, and, in addition, require a synchronized dual output. Utilizing the indexing cam structure of the aforementioned patent results in the substantial problem of synchronizing dual inputs with dual outputs and maintaining such an indexing cam structure synchronized during long periods of continuous operation.

I-Ieretofore, transfer mechanisms and in particular transfer mechanisms of the walking beam type have been employed in which cam devices have been used to impart motion between several movable members to move an article along a defined path. However, such cam devices lack the accuracy of the indexing cam structure of the aforementioned patent and in addition required numerous components; are very expensive to manufacture; are not reliable; and are short lived; resulting in a considerable downtime of the transfer mechanism and an increase in the overall cost of the product using such a transfer mechanism in its manufacture.

It is desirable to provide an indexing cam drive particularly adapted for converting a single rotating input into a plurality of intermittently or alternatingly rotating outputs which eliminates the aforementioned problems of having a multitude of components and a lack of synchronization between such components in their adaptation to a transfer mechanism.

SUMMARY OF THE INVENTION The present invention which will be described subsequently in greater detail comprises an indexing cam drive having a single rotary input shaft and two rotary output shafts disposed in a housing in a parallel relationship with the input shaft which is preferably centrally disposed between the two output shafts. Cam means carried by the input shaft operatively engage with cam followers in the output shafts in such a manner as to provide 180 rotation of one output shaft while the other output shaft is held stationary and 180 of rotation of the other output shaft while the first-mentioned output shaft is held stationary.

The indexing cam drive of the present invention finds particular application with respect to transfer mechanisms and in particular to transfer mechanisms of the walking beam type wherein alternately rotating output shafts are used to raise a horizontally disposed moveable support relative to a horizontally disposed fixed support on which a workpiece is resting. The movable support is adapted to be raised vertically to en gage the workpiece and raise the same vertically to clear the fixed support. The movable support moves the workpiece a predetermined distance substantially parallel with the horizontal fixed support and lowers the workpiece vertically onto the horizontal fixed support, whereupon the movable support returns along a horizontal path vertically displaced below the first-mentioned horizontal path to resume the cycle, and thus the movable support follows a rectangular path to move the workpiece through successive stations along a defined horizontal path.

It is therefore an object of the present invention to provide a new and improved indexing cam drive having a plurality of intermittently and alternatively rotating output shafis.

It is a further object of this invention to provide a mechanism utilizing such a cam indexing drive for providing both vertical and horizontal movement of a member along a rectangular path.

Other objects, advantages, and applications of the present invention will become apparent to those skilled in the art of cam indexing drives when the accompanying description of an example of the best mode contemplated for practicing the invention is read.

BRIEF DESCRIPTlON OF THE DRAWINGS The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views and in which:

FIG. 1 is a cross-sectional view through an indexing cam drive incorporating one embodiment of the present invention and taken along line ]l1l of RIG. 2;

FIG. 2 is an elevational view of the indexing cam drive of the present invention with portions thereof broken away to illustrate the cam and the cam followers;

FIG. 3 is a top plan view of a transfer mechanism incorporating the present invention; and

FIG. 4 is a side elevational view of the transfer mechanism illustrated in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings and particularly to FIGS. 1 and 2 wherein there is illustrated a preferred embodiment of the present invention in the form of an indexing cam drive comprising a housing 12 in which three parallel shafts 114i, 116 and 18 are rotatably mounted. Shaft 14 is the input or driver shaft, while shafts l6 and 1d are the output or driven shafts.

Shaft 14 is mounted in a pair of roller bearings 20 and 22 respectively disposed in a front wall 24 and rear wall 26 of the housing 12. Shaft M protrudes through the rear wall 26 and has a splined portion 28 to permit coupling thereof with a motor drive as will be explained.

The output shafts 16 and lit and their associated bearings and cam followers, as will be described hereinafter, are mirror images of one another and substantially identical, and therefore only the shaft 16 will be described.

The output shaft 16 is rotatably mounted in roller bearings 30 and 32 respectively carried in the front wall 24 and the rear wall 26 of the housing 12 with the output shaft 16 protruding through the front wall M and adapted to be connected to a mechanism that is desired to be driven.

The output shaft 16 has a cam follower wheel 3d fixedly mounted thereon by any suitable means such as a screw 3%, extending through an enlarged end portion 38 of the output shaft 16 and into the forward sidewall of the wheel 3%. The position of the wheel 34 on the output shaft 116 is set by means of sleeves l0 and All respectively disposed between the opposite sidewalls of the wheel 34 and the enlarged end portion 3% and bearing 32. The wheel 34 is provided with a plurality of radially extending arms, generally indicated at 42, Ml and 46.

The radially extending arms are angularly spaced from the radially extending arms 46, while the radially extending arms 44 are in axial alignment with each arm 42 and 46. Thus, the total number of radially extending arms 44 equals the sum of the total number of radially extending arms 42 and 46.

A plurality of cam followers 48 and 50 are carried by the wheel 34, the cam followers 48 being carried by the radially extending arms 42 and 44, while the cam followers 50 are carried by the radially extending arms 44 and 46, such that the followers 48 and 50 are angularly displaced with respect to each other about the shaft 16. The precise angle between each adjacent follower is determined by dividing 360 by the number of followers utilized, and, in the present embodiment, each adjacent follower 48 and 50 is angularly displaced by 45. The number of followers 48 and 50 is chosen so as to stop the shaft twice during each 360 of rotation thereof, as will be explained in greater detail hereinafter.

Each of the cam followers 48 and 50 includes a mounting shaft 52 and 54, respectively. The shafts 52 are received by bores 55 and 56 respectively in radial extending arms 42 and 44, while the shafts 54 are received by bores 56 and 57 respectively in radial extending arms 44 and 46. The shafts 52 and 54 are maintained in their respective bores by any suitable means, such as a press fit. A cylindrical casing 58 is rotatably mounted on each shaft 52 and 54 by any suitable antifriction bearing (not shown). It will be noted that the cylindrical casings 58 are rotatable about individual axes, which axes are parallel to both axes of the input shaft 14 and the output shaft 16.

The input shaft 14 has an enlarged center portion 60 forming a central annular flange 62. A pair of cams 64 and 66 are secured to the opposite sides of the flange 62 by means of nut and bolt assemblies 68. The profiles of the two earns 64 and 66 are identical, but, as is apparent in FIGS. 1 and 2, the earns 64 and 66 have been reversed and realigned to cooperate with the cam followers 48 and 50 in a manner which will be described in greater detail hereinafter.

The cam 64 has a circular dwell portion 64a; two rise portions 64b and 64b; and reentrant portions 64c and 64c; while the profile of the cam 66 has a circular dwell portion 66a; two rise portions 66b and 66b; and two reentrant portions 66c and 660.

Referring to the cam followers 48 and 50 carried by the output shaft 18 as illustrated in FIG. 2, it can be seen that during the dwell period of the output shaft 18 the dwell portion 64a of cam 64 contacts one of the forward cam followers 48 to prevent movement of the output shaft 18 in a counterclockwise direction, while at the same time the dwell portion 660 contacts one of the rear cam followers 50 to prevent rotation of the output shaft 18 in a clockwise direction. Thus, dur-- ing a dwell period, the output shaft 18 is securely locked in place. When the cams 64 and 66 have been rotated 180, the cam surfaces 64a and 66a will contact cam followers 48 and 50 carried on the output shaft 16 to prevent rotational movement thereof in the same manner as hereinbefore described in description of the output shaft 18.

The rotation of the output shafts l6 and 18 from one stop to the next is achieved by one of the rise portions of one of the cams contacting a respective cam follower, followed immediately by the rise portion of the other cam contacting another cam follower. For example, in FIGS. 1 and 2, assume that the input shaft 14 is rotating in a clockwise direction, the rise portion 66b of cam 66 will contact the follower 50 and commence moving the follower 50 to rotate the output shaft 16 in a counterclockwise direction. Thereafter, the rise portion 64b of the cam 64 will engage a cam 48 to continue the counterclockwise rotation of the output shaft 16. At the same time, the reentrant portion 666 will also permit the cam follower 50 to move downwardly after the rise portion 66b has been rotated thereby. The cam rises 66b and 64b will respectively engage cam followers 48 and 50 in the same manner, causing the output shaft 16 to continue to rotate in a counterclockwise direction. During engagement of the rise portions of the cams 64 and 66 with the output shaft 16, the dwell portions 64a and 66 are in contact with the cam followers carried by the shaft 18, and thus while the shaft 16 is rotating in a counterclockwise direction, the shaft 18 is in a nonrotating state. With the continued rotation of the cams 64 and 66, the dwell portions 64a and 66a will engage the cam followers 48 and 50 carried on the output shaft 16 to fix the position of the shaft 16 at an exact rotational position and hold it there, while at the same time, the rise portion 66b of the cam 66 is commencing to engage the cam follower 50 carried on the output shaft 18 and will start to rotate the output shaft 18 in a counterclockwise direction in the same manner as hereinbefore described in the description of the rotation of the output shaft 16.

Thus, for each 360 of rotation of the input shaft 14, the output shaft 16 will be indexed one step with a dwell period between each indexing and the shaft 18 will likewise be indexed one step with a dwell period before and after each indexing step. The indexing of the output shaft 18 occurs while the output shaft 16 is in the dwell period, and the indexing of the output shaft 16 occurs while the output shaft 18 is in the dwell period, resulting in an alternate indexing of the output shafts l6 and 18. I

It can thus be seen that when the indexing cam drive 10 is provided with one input directed to the input shaft 14, two alternately and synchronized outputs are delivered at the output shafts l6 and 18 and which will remain synchronized irrespective of the speed or direction of the input shaft 14.

Referring to FIGS. 3 and 4 wherein a transfer mechanism 70 is illustrated as incorporating the indexing cam drive 10 of the present invention and comprises a pair of longitudinally spaced, vertical supports 72 and 74 mounting transverse rods 76 and 78, respectively, upon which are secured a pair of parallel spaced upright fixed support rails 80 and 82. Each rail 80 and 82 has a series of longitudinally spaced and transversely aligned receptacles 84 and 86, respectively. Each transversely aligned pair of receptacles 84 and 86 is adapted to receive spaced workpieces W" as the workpieces W" are transferred in succession along the path defined by the support rails 80 and 82 in a manner which will be described in greater detail hereinafter.

The indexing cam drive 10 is mounted to the underside of the longitudinal rail 82 by means of a bracket 88 by any suitable fastening means (not shown). Longitudinal rail 82 also supports a power drive in the form of an electric motor 90 drivingly connected to a gearbox 92 by means of a drive coupling 94. Gearbox 92 is in turn suitably coupled to the input drive shaft 14 to rotate the same at a constant speed.

A pair of movable, transversely spaced upright support rails 96 and 98 are disposed between the fixed support rails 80 and 82. The movable support rails 96 and 98 are connected by transverse rods 100 which are longitudinally spaced along the length of the support rails 96 and 98. Support rails 96 and 98 are supported on their undersides by a plurality of transversely aligned pairs of bearings 102, each pair of bearings being longitudinally spaced to maintain the support rails 96 and 98 in a horizontal position and as will be described hereinafter are adapted to vertically raise and lower the support rails 96 and 98 with respect to the fixed rails 80 and 82. The movable support rails 96 and 98 are respectively provided with a plurality of longitudinally spaced receptacles 104 and 106. Each opposing pair of receptacles 104 and 106 being transversely aligned in the same manner as receptacles 84 and 86 are aligned as hereinbefore described.

The movable support rails 96 and 98 are adapted to successively raise the receptacles 104 and 106 vertically when the same are transversely aligned with the receptacles 84 and 86 to engage the workpiece W" and raise it from the receptacles 84 and 86; convey the workpiece W" horizontally in one direction to the next adjacent pair of transversely aligned receptacles 84 and 86; lower the workpiece W until it is received within the next adjacent pair of receptacles 84 and 86 and the receptacles 104 and 106 are below the receptacles M and 66 by a predetermined amount; and move in an opposite direction horizontally back to its initial position for effecting the horizontal transfer of another workpiece W in the same manner.

A sensing mechanism, a portion of which is illustrated at lilh, is associated with each receptacle M and d6. Sensing mechanism lltltl senses whether or not a workpiece W" is in the associated receptacles M and 66. Through suitable means which do not form a part of the present invention, a preceding pair of receptacles d and R06 are deactivated so as not to engage a workpiece W" disposed in the preceding pair of receptacles M and $6, and thus stops the horizontal movement of the workpiece 'W" from the preceding receptacle to the next, when the next receptacle is occupied by a workpiece W, while permitting the continued motion of the rail 96 and 96.

FIG. 4 illustrates the manner in which the bearings 3102 are mounted and the manner in which the movable support rails 96 and 9d are set in motion to transfer the workpiece W from one receptacle to the next adjacent receptacle in succession along the fixed rails tit) and M. A plurality of support shafts llllllla, 1110b and title are rotatably carried by means of downwardly extending flanges 1112 at longitudinally spaced points along the support rails 60 and d2. Bearing means (not shown) permit rotational movement of the shafts 110a, lll0b and llltlc about their longitudinal axes. Each shaft 1110a, 1110b and lltlc has a pair of spaced pivot arms, one of which is shown at TM in FlG. i. Bearings 102 are pivotably mounted to the ends of the pivot arms llld for relative rotational movement. The pivot arms lllld are transversely spaced :1 distance which is equal to the distance between the support rails 96 and 98, which, in turn, are adapted for horizontal sliding engagement on the rollers 1102. Each shaft lllltla, lllltlb and 1100, respectively, has a second pivot arm M611, 1116]; and lll6c, each in the form of a pair of flanges lid and M9 extending downwardly from the midsection of each shaft. The pivot arm lll6a carried by the shaft ll 10a is pivotally mounted to one end of an adjustable connecting arm 120. The other end of the adjustable connecting arm 120 engages one end of a crank arm 122 for both pivotal and rotational movement by means of a link 121. The other end of the crank arm 122 is connected by any suitable means to the output shaft 18. The remaining longitudinally spaced shafts llltlb and llllllc are attached to the adjustable connecting arm 126 by a connecting arm 1% such that the three pivot arms 116a, ll6b and l ll6c follow identical rotational paths about their respective shafts, as will be described hereinafter.

A bridge which is fastened to rails 96 and 9% is provided with an upright member 1126, the lower end of which extends downwardly for a rotary connection with one end of another connecting arm Uh, the opposite end of which is connected to a second crank am 1130 by a universal link 132. The crank arm H30 is attached by any suitable means to the output shaft 116 of the indexing cam drive 10. Each of the connecting arms H and llZd is provided with adjusting means 134, to vary their length. The adjusting means 134 may take the form of a screw and nut assembly which is well known in the art of such adjusting means.

When the electric motor 90 is actuated so as to supply a constant rotating motion to the input shaft M of the cam indexing drive 10, the cam rise portions 66b, 64b, 66b and 64b will successively engage the cam followers 4% and 50 of the output shaft 118 to rotate the same 180 while the dwell portion Ma and 66a engage the cam followers 98 and 50 of the output shaft 116 to maintain the output shaft 16 stationary. As the output shaft l8 rotates 180, the crank arm 122 will rotate the connecting arm T20 which, in turn, will pivot the connecting arms 116a, lll6b and 1116s to the position illustrated in phantom at A." Movement of the connecting arms 1116 to the position A rotates each shaft lllil about its axis to raise the pivot arms lid in an upwardly direction. Since the pivot arms 114 and their associated bearings 102 on each shaft lllltla, 11012 and 1100 are connected by the rod 124, the bearing 1102 on each of the shafts lllltl will rise simultaneously to a second horizontal position, thereby raising the movable support rails 96 and 98 from a first horizontal position to a second horizon tal position which, in the preferred embodiment, will raise the receptacles 1104i and M6 to a position above the receptacles M and 66. Since the receptacles 10d and 1106 are transversely aligned with the receptacles M and 96 when the movable rails 96 and 96 are vertically raised from one horizontal plane to a higher plane, the receptacles MM and 1106 will engage the workpieces W" and raise the workpieces W from their associated receptacles M and 86. As the input shaft M rotates through a second 360 of rotation, the dwell portions 64in and 66a engage the cam followers of the output shaft 116 to maintain the output shaft id in a nonrotating state, while at the same time the rise portions of the cams 64 and 66 engage the cam followers of the output shaft E6 to cause the same to rotate 180. As can best be seen in FIG. 6, as crank arm 1130 rotates in a clockwise direction, the vertical connecting arm 1126 is horizontally shifted to a second vertical position, indicated in phantom at B, and thus moves the support rails 96 and 96 with the workpieces W to a second position in which the receptacles MM and W6 will be in transverse alignment with the next adjacent pair of receptacles 84 and 636. As the input shaft 14 commences a second revolution, the dwell portion of the earns 66 and 66 will engage the cam followers 46 and 50 on the output shaft 16 and maintain the output shafts 116 in a nonrotating state, while at the same time the cams 66 and 64 will rotate the output: shaft 18 to cause the crank arm 122 to rotate in a clockwise direction. Rotation of the crank arm 1122 returns the pivot arms 1116 back to their ini tial position as illustrated in FIG. 4. Rotation of the pivot arms 1116 to their initial position will lower the bearings K02 and thus the movable support rails 96 and 98 back to their initial horizontal position, such that the receptacles 10d and ll06 are below the receptacles M and 66, thereby positioning the workpieces W" on the next adjacent pair of receptacles lid and 86.

Continued rotation of the input shaft 14 causes the dwell portion of the cams 6d and 66 to engage the output shaft lit and maintain the same in a nonrotating state while the rise portions of the cams 6d and 66 will engage and rotate the output shaft 16 for 180 to rotate the crank arm for in a clockwise direction, returning the vertical shaft 1l26 from the position indicated at B to its initial position as illustrated in FlG. 41, thereby returning the receptacles 110 i and 166 in line with the receptacles 64 and 86. Thus, it can be seen that by constant rotation of the input shaft M, the output shafts l6 and T8 are alternately indexed to rotate 180 and dwell for 180 thereby causing the movable support rails 96 and 9% to follow a generally rectangular path of: first, moving upwardly to engage the workpieces W" and removing them from their associated receptacles Ml and 96; second, traversing horizontally to the next successive pair of receptacles M5 and 96; third, moving vertically downwardly to deposit the workpiece W" in the next successive pair of receptacles M and 86; and fourth, traversing the support rails 96 and 98 back to their original starting position to recycle the process of moving the workpieces W in succession along the fixed rails 60 and 62.

It can thus be seen that the cam indexing device of the present invention provides a means of converting a single rotating input into two alternating rotating outputs which are always synchronized; and in the present application has provided a means for transferring workpieces in succession along a horizontal path.

Although the invention has been described with some particularity, it is to be understood that the particular embodiment shown may be modified and that numerous changes in the details of the construction and the arrangement of the parts may be had without departing from the spirit of the invention or the scope of the appended claims.

What is claimed is as follows:

It. An apparatus for producing intermittent motion in two horizontal planes in opposite directions and in two vertical planes in opposite directions comprising:

cam means having a continuous single rotary input and two alternately operative rotary outputs, said cam means alternately transmitting said rotary input to a first of said outputs to produce 180 of rotary motion thereof while a second of said outputs is in a nonrotating state, and for transmitting said rotary input to the second output to produce 180 of rotary motion thereof while said first output is in a nonrotating state,

a first member disposed in a horizontal plane and having a plurality of longitudinally spaced pairs of first receptacles;

a second member movable relative to said first member and having a plurality of longitudinally spaced pairs of second receptacles adapted for movement between said firstmentioned receptacles;

bearing means for supporting said second member for horizontal movement relative to said first member;

a first linkage means connecting said bearing means to said first output to move said bearing means between two horizontal planes in response to the alternate rotation of said first output;

second linkage means connecting said second member to said second output for moving said second member back and forth between two vertical planes in response to the alternate rotation of said second output; and

said cam means comprising a housing, a pair of output shafts and an input shaft disposed intermediate said output shafts, said shafts being rotatably mounted in said housing and positioned parallel to each other; a pair of wheels one of which is carried by one of said output shafts, the other carried by the other of said output shafts; a plurality of cam followers attached to each of said wheels and projecting outwardly from the sides of each wheel, each alternate follower projecting from an opposite side of each wheel a spaced angular distance from the adjacent follower of that wheel; a pair of cams attached to said input shaft, said cams being spaced to move at opposite sides of each of said wheels and to contact said followers of each wheel at said opposite sides of each wheel, each of said cams having a profile with a dwell portion thereon; each of said cams being in contact with one of said cam followers respectively on one wheel during said dwell portion for 180 rotation of said input shaft to fix the position of the output shaft of said wheel, each of said cams being in contact with one of said cam followers of the other of said wheels respectively during said dwell portion to fix the position of the other of said driven shafts during the other 180 of rotation of said input shafts, each cam having a reentrant portion in its profile at which it will move around a respective cam follower of each wheel, the portions of the profiles apart from the reentrant portion being a greater distance from the input shaft than are the profiles at the reentrant portions.

2. The apparatus defined in claim 1 wherein each of said shafts has a longitudinal axis, said shaft axes being parallel to each other, each of said wheels having two sets of cam followers, each cam follower having a cylindrical follower surface, each of said followers of each wheel being mounted on its associated wheel .and rotatable with respect to its associated wheel about an axis parallel to the axis of each output shaft, said followers of each wheel being positioned with their axes at spaced intervals about its associated wheel, one set of followers in each of said wheels being in one plane normal to said axes of its associated driven shaft, the other set of followers of each wheel being in a second plane normal to the axis of its associated output shaft and spaced from said first plane of its associated followers and being at a different angular position about the axis of its associated shaft than is the one set of cams in said associated shaft, the profile of one cam being positioned in one of said planes and the profile of the other cam being positioned in the other of said planes drawing a portion of rotation of said input shaft, and the profile of one of said cams being positioned in one of said planes of the other of said wheels, and the profile of the other cams being in the other of said planes of said other wheel during a second portion of the rotation of said input shaft, each profile having a reentrant portion at which the distance from the profile to the axis of the input shaft is substantially equal to the smallest distance of the follower surface to the axis of the input shaft as the followers move about its associated output shaft, the reentrant portion of one cam being angularly positioned with respect to the entrant portion of the other cam, each cam contacting a follower surface respectively in each wheel during 180 of dwell portion of the cams to fix the position of one output shaft during 180 of rotation and to fix the other output shaft during the remaining 1 of rotation of said input shaft.

3. A reciprocating conveyor comprising:

a. a stationary support frame having longitudinally spaced stationary part receptacles;

b. a vertically and horizontally reciprocable transfer frame having transfer receptacles for moving parts between successive stationary part receptacles; and

c. means effecting intermittent sequential reciprocation of said transfer frame, comprising a continuously rotating input cam assembly,

a first and second rotatable output driver member each alternately rotated a predetermined arcuate degree by said cam assembly while the other driver member is held stationary by said cam assembly, and

a first and a second linkage mechanism eccentrically pivotally secured respectively to said driver members for translating rotary motion thereof to reciprocating motion of said linkage mechanisms, the first linkage mechanism being operatively connected to intermittently vertically lift and lower said transfer frame by respectively successive rotations of its associated driver member providing dwell periods between such rotations, the second linkage mechanism being operatively connected to intermittently horizontally advance and return said transfer frame by respectively successive rotations of its associated drive member only during the dwell periods of said first linkage mechanism and providing dwell periods between such rotations during which said first linkage mechanism operates.

4. The conveyor as defined in claim 3 wherein said first linkage mechanism comprises; and arm eccentrically pivotally secured at one end to its associated driver member, and a rotatable shaft carried on a fixed axis beneath said transfer frame; said shaft having a first lever fixed thereto and connected with the other end of said arm for directly translating motion thereof to reciprocating partial rotation of said shaft, and a second lever fixed to said shaft and having a roller disposed in supporting contact with said transfer frame to intermittently lift and lower same while permitting horizontal reciprocation thereof on said roller.

5. The conveyor as defined in claim 4 wherein at least two such rotatable shafts are provided each having such second lever and roller, said rollers being the sole support for said transfer frame at least during movements thereof.

6. The conveyor defined in claim 3 wherein said transfer frame has a depending arm rigidly affixed thereto and said second linkage mechanism comprises an arm eccentrically pivotally secured at one end to its associated driver member and at the other end to said depending arm for directly transmitting horizontal reciprocating motion thereto.

7. The conveyor as defined in claim 3 wherein said linkage mechanisms are pivotally connected with said driver members through universal joint connections.

8. The conveyor as defined in claim 3 wherein said input cam assembly is disposed intermediate said output driver members.

9. The conveyor as defined in claim 8 wherein said linkage mechanisms include an arm eccentrically pivotally secured to each output driver member, and said arms respectively oppositely extend from said driver members.

cam lobes engage at least one arm to rotate said driver member a corresponding degree.

1111. The conveyor as defined in claim Ml wherein said cam member has a pair of axially adjacent cam lobe portions and said driver members each have alternate arms in axially adjacent planes disposed for engagement successively with said cam lobe portions for positive driving rotation of said driver member for the full corresponding degree of rotation thereof. 

1. An apparatus for producing intermittent motion in two horizontal planes in opposite directions and in two vertical planes in opposite directions comprising: cam means having a continuous single rotary input and two alternately operative rotary outputs, said cam means alternately transmitting said rotary input to a first of said outputs to produce 180* of rotary motion thereof while a second of said outputs is in a nonrotating staTe, and for transmitting said rotary input to the second output to produce 180* of rotary motion thereof while said first output is in a nonrotating state, a first member disposed in a horizontal plane and having a plurality of longitudinally spaced pairs of first receptacles; a second member movable relative to said first member and having a plurality of longitudinally spaced pairs of second receptacles adapted for movement between said first-mentioned receptacles; bearing means for supporting said second member for horizontal movement relative to said first member; a first linkage means connecting said bearing means to said first output to move said bearing means between two horizontal planes in response to the alternate rotation of said first output; second linkage means connecting said second member to said second output for moving said second member back and forth between two vertical planes in response to the alternate rotation of said second output; and said cam means comprising a housing, a pair of output shafts and an input shaft disposed intermediate said output shafts, said shafts being rotatably mounted in said housing and positioned parallel to each other; a pair of wheels one of which is carried by one of said output shafts, the other carried by the other of said output shafts; a plurality of cam followers attached to each of said wheels and projecting outwardly from the sides of each wheel, each alternate follower projecting from an opposite side of each wheel a spaced angular distance from the adjacent follower of that wheel; a pair of cams attached to said input shaft, said cams being spaced to move at opposite sides of each of said wheels and to contact said followers of each wheel at said opposite sides of each wheel, each of said cams having a profile with a dwell portion thereon; each of said cams being in contact with one of said cam followers respectively on one wheel during said dwell portion for 180* rotation of said input shaft to fix the position of the output shaft of said wheel, each of said cams being in contact with one of said cam followers of the other of said wheels respectively during said dwell portion to fix the position of the other of said driven shafts during the other 180* of rotation of said input shafts, each cam having a reentrant portion in its profile at which it will move around a respective cam follower of each wheel, the portions of the profiles apart from the reentrant portion being a greater distance from the input shaft than are the profiles at the reentrant portions.
 2. The apparatus defined in claim 1 wherein each of said shafts has a longitudinal axis, said shaft axes being parallel to each other, each of said wheels having two sets of cam followers, each cam follower having a cylindrical follower surface, each of said followers of each wheel being mounted on its associated wheel and rotatable with respect to its associated wheel about an axis parallel to the axis of each output shaft, said followers of each wheel being positioned with their axes at spaced intervals about its associated wheel, one set of followers in each of said wheels being in one plane normal to said axes of its associated driven shaft, the other set of followers of each wheel being in a second plane normal to the axis of its associated output shaft and spaced from said first plane of its associated followers and being at a different angular position about the axis of its associated shaft than is the one set of cams in said associated shaft, the profile of one cam being positioned in one of said planes and the profile of the other cam being positioned in the other of said planes drawing a portion of rotation of said input shaft, and the profile of one of said cams being positioned in one of said planes of the other of said wheels, and the profile of the other cams being in the other of said planes of said other wheel during a second portion of the rotation of said input shaft, each profIle having a reentrant portion at which the distance from the profile to the axis of the input shaft is substantially equal to the smallest distance of the follower surface to the axis of the input shaft as the followers move about its associated output shaft, the reentrant portion of one cam being angularly positioned with respect to the entrant portion of the other cam, each cam contacting a follower surface respectively in each wheel during 180* of dwell portion of the cams to fix the position of one output shaft during 180* of rotation and to fix the other output shaft during the remaining 180* of rotation of said input shaft.
 3. A reciprocating conveyor comprising: a. a stationary support frame having longitudinally spaced stationary part receptacles; b. a vertically and horizontally reciprocable transfer frame having transfer receptacles for moving parts between successive stationary part receptacles; and c. means effecting intermittent sequential reciprocation of said transfer frame, comprising a continuously rotating input cam assembly, a first and second rotatable output driver member each alternately rotated a predetermined arcuate degree by said cam assembly while the other driver member is held stationary by said cam assembly, and a first and a second linkage mechanism eccentrically pivotally secured respectively to said driver members for translating rotary motion thereof to reciprocating motion of said linkage mechanisms, the first linkage mechanism being operatively connected to intermittently vertically lift and lower said transfer frame by respectively successive rotations of its associated driver member providing dwell periods between such rotations, the second linkage mechanism being operatively connected to intermittently horizontally advance and return said transfer frame by respectively successive rotations of its associated drive member only during the dwell periods of said first linkage mechanism and providing dwell periods between such rotations during which said first linkage mechanism operates.
 4. The conveyor as defined in claim 3 wherein said first linkage mechanism comprises; and arm eccentrically pivotally secured at one end to its associated driver member, and a rotatable shaft carried on a fixed axis beneath said transfer frame; said shaft having a first lever fixed thereto and connected with the other end of said arm for directly translating motion thereof to reciprocating partial rotation of said shaft, and a second lever fixed to said shaft and having a roller disposed in supporting contact with said transfer frame to intermittently lift and lower same while permitting horizontal reciprocation thereof on said roller.
 5. The conveyor as defined in claim 4 wherein at least two such rotatable shafts are provided each having such second lever and roller, said rollers being the sole support for said transfer frame at least during movements thereof.
 6. The conveyor defined in claim 3 wherein said transfer frame has a depending arm rigidly affixed thereto and said second linkage mechanism comprises an arm eccentrically pivotally secured at one end to its associated driver member and at the other end to said depending arm for directly transmitting horizontal reciprocating motion thereto.
 7. The conveyor as defined in claim 3 wherein said linkage mechanisms are pivotally connected with said driver members through universal joint connections.
 8. The conveyor as defined in claim 3 wherein said input cam assembly is disposed intermediate said output driver members.
 9. The conveyor as defined in claim 8 wherein said linkage mechanisms include an arm eccentrically pivotally secured to each output driver member, and said arms respectively oppositely extend from said driver members.
 10. The conveyor as defined in claim 3 wherein said input cam assembly comprises a cam member formed with a predetermined peripheral portion of constant radius and the remaining peripHeral portion of cam lobes, and each output driver member comprises radial arcuately spaced arms constantly engaged with said cam member such that for a predetermined degree of rotation thereof said radius engages intermediate adjacent arms of one driver member to retain same stationary and for the remaining degree of rotation said cam lobes engage at least one arm to rotate said driver member a corresponding degree.
 11. The conveyor as defined in claim 10 wherein said cam member has a pair of axially adjacent cam lobe portions and said driver members each have alternate arms in axially adjacent planes disposed for engagement successively with said cam lobe portions for positive driving rotation of said driver member for the full corresponding degree of rotation thereof. 